Bees infected with a common gut parasite work less, die younger and carry much less pollen than healthy bees, Queensland researchers have found.

The finding is significant for humans, given about a quarter of food production depends on honey bee pollination.

James Cook University researchers made the discovery after gluing tiny transmitters to the backs of 960 bees and then infecting half with a low dose of nosema spores, a gut parasite common among the adult insects.

“No one had looked at bees at this level before, to see what individual bees do when they are sick,” lead researcher Dr Lori Lach said.

The tagged bees were observed visiting hives and artificial flowers. Researchers found the bees infected with the gut parasite were 4.3 times less likely to be carrying pollen than uninfected bees, and carried less pollen when they were. They also found the sick insects started working later, stopped working sooner and died younger.

Lach said the research was vital to understanding how bees were affected by non-lethal stressors.

The nosema apis parasite was long thought to be benign compared with other parasites and pathogens that infect #honey bees, and it was the first time its effect on bee behaviour had been examined, she said.

Lach said the real implications from this work were for humans.

“Declines in the ability of honey bees to #pollinate will result in lower crop yields,” she said.